An Open Source 96 MSPS Logic Analyzer For $22

If you are in the market for an inexpensive USB logic analyser you have a several choices, but few of them deliver much in the way of performance. There are kits from China for a few dollars using microcontrollers at their heart, but they fail to deliver significant sample rates. If you require more, you will have to pay for it.

It is therefore rather interesting to see [kevinhub88]’s SUMP2 project, an open source logic analyser with a claimed 96 MSPS sample rate using an off-the-shelf Lattice iCEstick FPGA evaluation board that only costs about $20. It talks to a host computer via USB using the established SUMP protocol, so its software front-end comes from the sump.org logic analyser project. Edit: Since this post was published [Kevin] has contacted us to inform us that the project’s capabilities have now moved beyond SUMP’s capabilities and in fact it now uses his own software.

This project has the promise to add a very useful piece of test equipment to the armoury of the engineer on a budget, and to aid the cost-conscious reader he’s provided extensive documentation and installation instructions, as well as the code for the FPGA. Thanks to one of the more awesome hacks of 2015, there is an entirely open toolchain for this Lattice part, and our own [Al Williams] has written up a multi-part getting-started guide if you want to get your feet wet. You probably want one of these anyway, and now it’s a logic analyzer to boot.

We’ve covered quite a few inexpensive home-produced digital instruments here over the years, including this logic analyser with a slightly higher price tag, this inexpensive VNA, and this oscilloscope board. Maybe one day the bench of our dreams will all come on one open-source PCB for $100, who knows!

Open Design Oscilloscope Could be (Almost) Free

If you could only own one piece of test equipment, it should probably be an oscilloscope. Then again, modern scopes often have multiple functions, so maybe that’s not a fair assertion. A case in point is the Scopefun open hardware project. The device is a capable 2-channel scope, a logic analyzer and also a waveform and pattern generator. The control GUI can work with Windows, Linux, or the Mac (see the video, below).

The hardware uses a Xilinx Spartan-6 FPGA. A GUI uses a Cypress’s EZ-USB FX2LP chip to send configuration data to the FPGA.  Both oscilloscope channels are protected for overvoltage up to +/- 50 V. The FPGA samples at 100 Mhz through a 10-bit dual analog-to-digital converter ( ADC ). The FPGA handles triggering and buffers the input before sending the data to the host computer via the USB chip. Each channel has a 10,000 sample buffer.

There are also two generator outputs with short circuit and overvoltage protection ( +/- 50 V ). Generator channels have 50 Ohm internal impedance and also operates via the GUI using the same USB chip. The FPGA generates signals at 50 Mhz using counters, algorithms, or simple waveform data and feeds a DAC.

A 16-bit digital interface can be set as inputs or outputs. The FPGA samples inputs at 100 MHz. The output voltage can be set, but inputs are 5 V tolerant.

According to the developer, you can build the scope from the information provided by using free sample chips from the various vendors, only paying for the small components and the cost of the PCB.

We’ve looked at several low-cost scope options before. Labtool even boasts some similar features.

Hackaday Prize Entry: FPGAs For The Raspberry Pi Zero

The Raspberry Pi is the Arduino of 2016, and that means shields, hats, add-ons, and other fun toys that can be plugged right into the GPIO pins of a Pi. For this year’s Hackaday Prize, [Valentin] is combining the Pi with the next age of homebrew computation. He’s developed the Flea Ohm, an FPGA backpack or hat for the Pi Zero.

The Flea Ohm is based on Lattice’s ECP5 FPGA featuring 24k LUTs and 112kB BRAM. That’s enough for some relatively interesting applications, but the real fun comes from the added 32MB or 128MB of SDRAM, a micro SD card slot, USB + PS/2 host port and an LVDS output.

The combination of Raspberry Pis and FPGAs are extremely interesting and seem to be one of the best FPGA learning platforms anyone can imagine. Another Hackaday Prize entry, the ZinqBerry does a similar trick, but instead of a Pi hat, the ZinqBerry drops a Xilinx Zynq with an FPGA and ARM Cortex A9 core onto a board with Ethernet, HDMI, and USB.

If it’s a Flea or a Zinq, the age of FPGA’d Raspberry Pis is quickly approaching, and hopefully we’ll see them as finalists in the Hackaday Prize. You can check out a video of the Flea Ohm below.

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Retro-Soviet Computer Brings The 80s Back

[Alex Zaikin] made a modern reproduction of an early-80s Soviet hobbyist home computer. Although the design was open, indeed it was published in “Radio” magazine, the project was a mammoth undertaking involving around 200 microchips, so not many “Mikro-80” computers were actually made.

[Alex] wanted to simplify the project and reduce the parts count. These days, 200 microchips’ worth of logic can easily fit inside an FPGA, and [Alex] wrangled the chip count down to seven. Moreover, he made it even easier to build your own retro minicomputer by building a modular platform: Retrobyte.

With the Retrobyte providing all of the essential infrastructure — SD card, tape recorder I/O, VGA outputs, and more — and the FPGA providing the brains, all that was left was to design a period keyboard and 3D print a nice enclosure. Project complete! Time for a few rounds of ASCII Tetris to celebrate.

We’ve covered a number of retro computer projects. We just have a soft spot for them, is all. If you don’t know what all the fuss is about, you could start out with a kit build to get your feet wet. Before long, you’ll be emulating ever obscurer computers of yore in custom logic. And when you do, be sure to drop us a line!

DEF CON: BSODomizing In High Definition

A few years ago, [Kingpin] a.k.a. [Joe Grand] (A judge for the 2014 Hackaday Prize) designed the most beautiful electronic prank ever. The BSODomizer is a simple device with a pass-through connection for a VGA display and an infrared receiver. Plug the BSODomizer into an unsuspecting coworker’s monitor, press a button on a remote, and watch Microsoft’s blue screen of death appear. It’s brilliant, devious, and actually a pretty simple device if you pick the right microcontroller.

The original BSODomizer is getting a little long in the tooth. VGA is finally dead. The Propeller chip used to generate the video only generates text, and can’t reproduce Microsoft’s fancy new graphical error screens. HDMI is the future, and FPGAs have never been more accessible. For this year’s DEF CON, [Kingpin] and [Zoz] needed something to impress an audience that is just learning how to solder. They’ve revisited the BSODomizer, and have created the greatest hardware project at this year’s DEF CON.

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The Perfect Storm: Open ARM + FPGA Board

Playing around with FPGAs used to be a daunting prospect. You had to fork out a hundred bucks or so for a development kit, sign the Devil’s bargain to get your hands on a toolchain, and only then can you start learning. In the last few years, a number of forces have converged to bring the FPGA experience within the reach of even the cheapest and most principled open-source hacker.

[Ken Boak] and [Alan Wood] put together a no-nonsense FPGA board with the goal of getting the price under $30. They basically took a Lattice iCE40HX4K, an STMF103 ARM Cortex-M3 microcontroller, some SRAM, and put it all together on a single board.

The Lattice part is a natural choice because the IceStorm project created a full open-source toolchain for it. (Watch [Clifford Wolf]’s presentation). The ARM chip is there to load the bitstream into the FPGA on boot up, and also brings USB connectivity, ADC pins, and other peripherals into the mix. There’s enough RAM on board to get a lot done, and between the ARM and FPGA, there’s more GPIO pins than we can count.

Modeling an open processor core? Sure. High-speed digital signal capture? Why not. It even connects to a Raspberry Pi, so you could use the whole affair as a high-speed peripheral. With so much flexibility, there’s very little that you couldn’t do with this thing. The trick is going to be taming the beast. And that’s where you come in.

Amazing SDR Built by 16 Year Old

[Lukas] started his epic SDR-from-scratch build when he was 16. Projects like this aren’t completed overnight. (He’s now 18. We’re impressed.)

The project itself is a Software-Defined Radio built on top of the 12-bit Analog Devices AD9364 transceiver IC. A big fat FPGA takes the data and runs it off to a USB 3.0 interface, which is necessary for the amount of data this thing will be producing — he’s got it receiving 56 MHz of bandwidth. In short, this is an SDR peripheral that’s in the big leagues.

After two years of work and (only!) three revision, [Lukas] got the thing working. Read his writeup for the blow-by-blow account. In the end, a 6-layer board was necessary for the routing to get the full speed out of the clocking, and he discovered the reason that you use exactly the specified bias resistors — the expensive ADC chip gets very hot. But he didn’t give up, and in the end he pulled off a project of immense complexity. In his own words:

I have discovered that taking on large projects, even when not knowing how to tackle problems that might arise, is a very effective way of learning for me. It’s just important to be persistent, as I’ve seen that almost any problem can be solved on your own — which is incredibly rewarding — even if you get stuck and seem to not make progress for a while.

[Lukas] is now working on the software. He’s already got a hacked osmocom driver working, so it plays nice with GNURadio.

Of course, there are tons of ways to get into SDR without building your own from scratch, but we applaud [Lukas] for going the hard way. If you’re tempted to follow in his footsteps, have a look at [Michael Ossmann]’s great talk on making the RF design process as tractable as possible.